Elongator subunit Elp3 regulates reproduction in Tribolium castaneum by interacting with FOXO

As the catalytic subunit of the Elongator complex, Elongator protein 3 (Elp3) plays a crucial role in multiple physiological processes, including growth, development and immune responses. Previous studies on Elp3 have focused on Caenorhabditis elegans, Drosophila melanogaster, Homo sapiens (human) or Mus musculus (mouse), whereas there are few reports on Elp3 in agricultural pests. Here, the role of TcElp3 in reproduction in the red flour beetle, Tribolium castaneum, was investigated, and the underlying mechanisms were explored. The results showed that RNA interference (RNAi)-mediated knockdown of TcElp3 in female pupae led to decreased fecundity in female adults. Consistently, the injection of dsTcElp3 into female pupae decreased the mRNA levels of the vitellogenin (Vg)-encoding genes TcVg1 and TcVg2 in female adults. Notably, knockdown of TcElp3 upregulated the expression of forkhead box protein O (FOXO) at both the mRNA and the protein level in T. castaneum, and promoted the nuclear translocation of TcFOXO. Additionally, TcElp3 directly interacts with TcFOXO and the silencing of TcElp3 significantly decreased the acetylation level of TcFOXO. Overall, our studies reveal that Elp3 regulates beetle reproduction by interacting with FOXO and modulating its acetylation status.